Method for manufacturing structural member and structural member

Abstract

To provide a manufacturing method of a structural member which can be manufactured by a compact device, and to provide the structural member.SOLUTION: The method for manufacturing a structural member includes an outer shell portion forming step of forming the tubular outer shell portion 31 having the up-down direction as the axial direction by performing at least one of lamination and injection of the shaping material a discharged from the discharge port 11a of the manufacturing device 1 upward from below, and an inner shell portion forming step of forming the inner shell portion 32 inside the outer shell portion by injecting the shaping material b from the manufacturing device 2 toward the inside of the outer shell portion 31.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a structural member and a structural member. [Background technology]

[0002] Conventionally, various types of precast concrete piles have been known, including PHC piles, SC piles, and RC piles. Many of these piles are manufactured using centrifugal forming. For example, PHC piles are manufactured by placing a reinforcing bar cage in a cylindrical steel formwork, pouring concrete into it, compacting it using centrifugal force, and then dehydrating the excess water in the concrete to form it into a hollow pile.

[0003] In recent years, structures such as piles have also been constructed using 3D printers. As disclosed in Patent Document 1 below, a method is known in which a structure is constructed by stacking modeling materials using a 3D printer to create a base, and then spraying a spraying material onto the outer periphery (surface) of the base to form a surface layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-195731 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the above manufacturing method, when spraying the spray material onto the outer surface of the foundation to form the surface layer, the 3D printer needs to move around the outer periphery of the foundation, which presents a problem in that the 3D printer needs to be moved significantly.

[0006] The present invention has been made in view of the above circumstances, and provides a method for manufacturing a structural member that can be manufactured using a compact device, and a structural member. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention employs the following means. In other words, the manufacturing method of a structural member according to the present invention comprises an outer shell forming process in which a molding material is stacked or sprayed from a manufacturing device from bottom to top to form a cylindrical outer shell with an axial direction in the vertical direction, and an inner shell forming process in which the molding material is sprayed from the manufacturing device toward the inside of the outer shell to form an inner shell inside the outer shell.

[0008] In the method for manufacturing a structural member configured in this manner, a cylindrical outer shell is formed by a manufacturing device in the outer shell forming step, and an inner shell is formed inside the outer shell by the manufacturing device in the inner shell forming step. Because the outer shell is formed by the manufacturing device and then sprayed toward the interior, there is no need for the manufacturing device to orbit the outer shell after forming the outer shell. Since the manufacturing device only needs to be located inside the outer shell, it can be made into a compact device.

[0009] Furthermore, in the method for manufacturing a structural member according to the present invention, the manufacturing apparatus for the outer shell portion molding process may be a first manufacturing apparatus, and the manufacturing apparatus for the inner shell portion molding process may be a second manufacturing apparatus, and the manufacturing apparatus for the outer shell portion molding process and the manufacturing apparatus for the inner shell portion molding process may be different.

[0010] In the method for manufacturing a structural member configured in this manner, the manufacturing device used in the outer shell molding step is the first manufacturing device, and the manufacturing device used in the inner shell molding step is the second manufacturing device, so that the outer shell molding step and the inner shell molding step can be carried out more efficiently.

[0011] In the method for manufacturing a structural member according to the present invention, the inside of the inner shell portion may be formed to be hollow.

[0012] In the method for manufacturing a structural member configured in this manner, hollow structural members can be manufactured efficiently.

[0013] In the method for manufacturing a structural member according to the present invention, the outer shell molding step of molding the outer shell may be carried out while the inner shell molding step of molding the inner shell is carried out simultaneously.

[0014] In the method for manufacturing a structural member configured in this manner, the outer shell molding process for molding the outer shell and the inner shell molding process for molding the inner shell are carried out simultaneously, thereby enabling more efficient manufacturing and shortening the time required to manufacture a structural member.

[0015] In the method for manufacturing a structural member according to the present invention, the inner shell molding step of molding the inner shell may be carried out after the molding of the outer shell is completed in the outer shell molding step.

[0016] In this method for manufacturing a structural member, the inner shell portion is formed by the second manufacturing device after the outer shell portion has been formed. This prevents the manufacturing devices from interfering with each other when manufacturing a single structural member, allowing the work to proceed smoothly.

[0017] In addition, the manufacturing method of a structural member according to the present invention may include a reinforcing material placement process for placing a reinforcing material inside the outer shell portion, and in the inner shell portion molding process, the molding material may be sprayed from the manufacturing device toward the reinforcing material to mold the inner shell portion including the reinforcing material.

[0018] In the method for manufacturing a structural member configured as described above, the manufacturing device sprays the molding material toward the reinforcement material placed in the reinforcement material placement step, thereby forming an inner shell portion including the reinforcement material, thereby increasing the strength of the structural member.

[0019] In addition, the manufacturing method of a structural member according to the present invention may include a reinforcing material placement process for placing a reinforcing material, wherein in the outer shell molding process, the outer shell is molded outside the reinforcing material, and in the inner shell molding process, the molding material is sprayed from the manufacturing device toward the reinforcing material to form the inner shell including the reinforcing material.

[0020] In the method for manufacturing a structural member configured as described above, the manufacturing device sprays the molding material toward the reinforcement material placed in the reinforcement material placement step, thereby forming an inner shell portion including the reinforcement material, thereby increasing the strength of the structural member.

[0021] In addition, the structural member of the present invention comprises an outer shell portion formed into a cylindrical shape with an axial direction in the vertical direction by stacking or spraying and hardening the molding material discharged from the manufacturing device, and an inner shell portion formed inside the outer shell portion by spraying the molding material discharged from the manufacturing device toward the inside of the outer shell portion and hardening.

[0022] In a structural component configured in this manner, a manufacturing device forms a cylindrical outer shell portion, and then forms an inner shell portion inside the outer shell portion. Because the outer shell portion is formed by the manufacturing device and then sprayed toward the interior, the manufacturing device does not need to orbit the outer shell portion after forming the outer shell portion. Because the manufacturing device only needs to be located inside the outer shell portion, the structural component can be manufactured using a compact device. [Effects of the Invention]

[0023] According to the method for manufacturing a structural member and the structural member of the present invention, they can be manufactured using a compact device. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a perspective view illustrating a method for manufacturing a structural member according to a first embodiment of the present invention. [Figure 2] 3 is a perspective view showing the method for manufacturing a structural member according to the first embodiment of the present invention, illustrating a step subsequent to that shown in FIG. 2. FIG. [Figure 3] 4 is a perspective view showing the method for manufacturing a structural member according to the first embodiment of the present invention, illustrating a step subsequent to that shown in FIG. 3. FIG. [Figure 4] 1A to 1C are plan views illustrating a method for manufacturing a structural member according to a first embodiment of the present invention. [Figure 5] FIG. 10 is a perspective view showing a method for manufacturing a structural member according to a second embodiment of the present invention. [Figure 6] 5. FIG. 6 is a perspective view showing a method for manufacturing a structural member according to a second embodiment of the present invention, showing a step subsequent to that shown in FIG. [Figure 7] 7 is a perspective view showing a method for manufacturing a structural member according to a second embodiment of the present invention, illustrating a step subsequent to that shown in FIG. 6. FIG. [Figure 8] 10A to 10C are plan views illustrating a method for manufacturing a structural member according to a second embodiment of the present invention. [Figure 9] FIG. 10 is a perspective view showing a method for manufacturing a structural member according to a third embodiment of the present invention. [Figure 10] FIG. 1 is a perspective view showing a structural member manufactured by a manufacturing method for a structural member according to a first modified example of the embodiment of the present invention. [Figure 11] FIG. 10 is a perspective view showing a structural member manufactured by a method for manufacturing a structural member according to a second modified example of the embodiment of the present invention. [Figure 12] FIG. 10 is a perspective view showing a structural member manufactured by a structural member manufacturing method according to a third modified example of the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] (First embodiment) Hereinafter, a method for manufacturing a structural member and a structural member according to a first embodiment of the present invention will be described with reference to the drawings. 1 to 3 are perspective views showing a method for manufacturing a structural member according to a first embodiment of the present invention. Fig. 2 shows a process subsequent to that shown in Fig. 1. Fig. 3 shows a process subsequent to that shown in Fig. 2. 1, the method for manufacturing a structural member according to this embodiment uses a first manufacturing apparatus (manufacturing apparatus) 1 and a second manufacturing apparatus (manufacturing apparatus) 2. The first manufacturing apparatus 1 and the second manufacturing apparatus 2 are additive manufacturing apparatuses that manufacture a structural member 3 using a modeling material.

[0026] The first manufacturing apparatus 1 has a first nozzle 11 and a first moving unit 12. The first nozzle 11 ejects the molding material a from an outlet 11a at the tip of the first nozzle 11. The first moving unit 12 moves the first nozzle 11. The first moving unit 12 is, for example, a robot arm. The first nozzle 11 ejects the molding material a so that it is layered from below upward. Note that the first nozzle 11 may also spray the molding material a from below upward. The first manufacturing apparatus 1 forms an outer shell portion 31 that forms the outside of the structural member 3.

[0027] The second manufacturing apparatus 2 has a second nozzle 21 and a second moving unit 22. The molding material b is ejected from the ejection port 21a of the second nozzle 21. The second moving unit 22 moves the second nozzle 21. The second moving unit 22 is, for example, a robot arm. The second nozzle 21 sprays the molding material b. The second manufacturing apparatus 2 forms an inner shell portion 32 that forms the inside of the structural member 3.

[0028] Examples of building materials a and b include hydraulic mixtures, resin-based materials, and metal-based materials. Hydraulic mixtures include various cement-based materials (e.g., cement paste, mortar, concrete), geopolymer compositions, etc. Various short fibers may be added to hydraulic mixtures and resin-based materials. The short fibers added can be either chemically synthesized polymer fibers or inorganic fibers. Examples of chemically synthesized polymer fibers include polypropylene fiber, polyvinyl alcohol fiber, polyethylene fiber, polyester fiber, and aramid fiber. Examples of inorganic fibers include glass fiber, steel fiber, carbon fiber, rock fiber (e.g., basalt), ceramic fiber, and silica fiber. The fibers used do not necessarily have to be of a single type; multiple types of fibers with different diameters, lengths, and types can be used in different mixture ratios. The added fibers can also be expected to improve the mechanical properties of the hydraulic mixture after it hardens. Specifically, they can suppress shrinkage cracking and improve compressive strength, toughness, and tensile strength and toughness.

[0029] The modeling material a dispensed by the first manufacturing device 1 and the modeling material b dispensed by the second manufacturing device 2 may be the same or different. If the modeling material a used by the first manufacturing device 1 is a high-strength and high-toughness material, the mechanical performance of the outer shell structure (the outermost part of the cross section) will be improved, and the bending strength and bending toughness of the component will be improved. The modeling material b dispensed by the second manufacturing device 2 is preferably a hydraulic mixture.

[0030] The first manufacturing apparatus 1 and the second manufacturing apparatus 2 are controlled by a control unit (not shown) so as to discharge modeling materials a and b at predetermined positions based on design data such as design drawings.

[0031] The method for manufacturing a structural member includes an outer shell molding step and an inner shell molding step.

[0032] FIG. 4 is a plan view illustrating a method for manufacturing a structural member according to an embodiment of the present invention. In the outer shell molding process, the first nozzle 11 of the first manufacturing device 1 ejects the molding material a so as to be layered on the upper side of the support stand P. When viewed from above, the first nozzle 11 moves in the circumferential direction, layering the material once, then moves upward, and repeats this process of layering the material once again in the circumferential direction on the upper side, then moving upward again. The molding material a layered from the first nozzle 11 forms a cylindrical outer shell 31 whose axis is in the vertical direction. As shown in FIG. 4, the ejection port 11a of the first nozzle 11 is located above the outer shell 31.

[0033] 2 and 3, the height of the outer shell portion 31 gradually increases as the process proceeds. When the outer shell portion 31 reaches a predetermined height, the ejection of the modeling material a from the first nozzle 11 ends. Note that the shape of the outer shell portion 31 is not limited to a cylindrical shape, and may be a cylindrical shape that is rectangular in a plan view, and any shape can be set as long as it is cylindrical.

[0034] As shown in FIG. 1, in the inner shell forming process, the second nozzle 21 of the second manufacturing device 2 ejects the molding material b toward the inside of the outer shell 31. As shown in FIG. 4, the ejection port 21a of the second nozzle 21 is located inside the inner shell 32. When viewed from above, the second nozzle 21 moves circumferentially, moves upward, then moves around once, and then moves upward again. The ejection direction of the second nozzle 21 may be horizontal, diagonally downward, or diagonally upward. The molding material b ejected from the second nozzle 21 forms a cylindrical inner shell 32 whose axis is in the vertical direction. The inner shell 32 is located inside the outer shell 31. The outer shell 31 and inner shell 32 are continuously integrated in the radial direction to produce a cylindrical structural member 3. The structural member 3 can be used as a pile or precast pillar.

[0035] The first manufacturing device 1 and the second manufacturing device 2 are operated simultaneously. While the outer shell molding process for molding the outer shell 31 is proceeding, the inner shell molding process for molding the inner shell 32 is proceeding at the same time. In other words, while the molding material a is being layered from the first nozzle 11, the molding material b is being sprayed from the second nozzle 21.

[0036] In the manufacturing method for a structural member configured in this manner, a cylindrical outer shell 31 is formed by a first manufacturing apparatus 1 in an outer shell forming process, and an inner shell 32 is formed inside the outer shell 31 by a second manufacturing apparatus 2 in an inner shell forming process. After the outer shell 31 is formed by the first manufacturing apparatus 1, the second manufacturing apparatus 2 sprays it toward the inside, so there is no need for the second manufacturing apparatus 2 to circle around the outer shell 31 after forming the outer shell 31. The second manufacturing apparatus 2 only needs to be positioned inside the outer shell 31, so the apparatus can be made compact.

[0037] In the outer shell molding process, the molding material a is discharged in a layered manner from the first nozzle 11 of the first manufacturing device 1. Layering allows for more accurate molding than spraying (ejection), making it easy to manufacture components with a beautiful appearance and high external dimensional accuracy.

[0038] Furthermore, in the inner shell forming step, the hollow inner shell 32 is formed inside the outer shell 31 by the second manufacturing device 2. Therefore, the hollow structural member 3 can be manufactured efficiently.

[0039] Furthermore, the outer shell molding process for molding the outer shell 31 and the inner shell molding process for molding the inner shell 32 are carried out simultaneously. This allows for more efficient manufacturing, and shortens the time required to manufacture the structural member 3.

[0040] In addition, in the inner shell molding process, the thickness of the molding material b sprayed onto the inside of the outer shell 31 by the second manufacturing device 2 can be changed to change the thickness of the inner shell 32, i.e., the thickness of the structural member 3 formed integrally by the outer shell 31 and the inner shell 32.

[0041] Second Embodiment Next, a second embodiment of the present invention will be described mainly with reference to Figures 5 to 8. In the following description of the embodiment, the same or similar members and parts as those in the above-described embodiment will be designated by the same reference numerals, and a description thereof will be omitted, and only configurations different from the embodiment will be described.

[0042] 5 to 7 are perspective views showing a manufacturing method of a structural member according to a first embodiment of the present invention. Fig. 6 shows a process subsequent to Fig. 5. Fig. 7 shows a process subsequent to Fig. 6. As shown in FIGS. 5 to 7, the method for manufacturing a structural member according to this embodiment includes a reinforcing material arranging step, an outer shell forming step, and an inner shell forming step.

[0043] As shown in FIG. 5, the reinforcement 4 installed in the reinforcement placement process includes a plurality of axial reinforcing bars 41 and a plurality of tie bars 42. The axial reinforcing bars 41 are long reinforcing bars. The plurality of axial reinforcing bars 41 are arranged at intervals in the circumferential direction. The tie bars 42 are formed in a ring shape. The plurality of tie bars 42 are arranged so as to surround the outside of the plurality of axial reinforcing bars 41. The plurality of tie bars 42 are arranged at intervals in the axial direction of the axial reinforcing bars 41. The shape of the reinforcement 4 is not limited to a cylindrical shape and may be a cylindrical shape that is rectangular in plan view, and any shape can be set as long as it is cylindrical.

[0044] In the reinforcing material placement step, the reinforcing material 4 is placed on the upper side of the support base P with the axial direction of the axial reinforcing bars 41 facing the up-down direction.

[0045] In the outer shell forming process, the first nozzle 11 of the first manufacturing device 1 discharges the molding material a in layers onto the upper side of the support stand P and outside the reinforcing material 4. When viewed from above, the first nozzle 11 moves circumferentially, depositing the material once, then moves upward, and repeats this process of depositing the material once again in the circumferential direction from the upper side, then moving upward. The molding material a deposited from the first nozzle 11 forms a cylindrical outer shell 31A with its axis in the vertical direction.

[0046] FIG. 8 is a plan view showing a method for manufacturing a structural member according to a second embodiment of the present invention. 8, the outer shell portion 31A is formed on the outside of the reinforcing material 4. Note that a portion of the reinforcing material 4 may be embedded in the inner peripheral portion of the outer shell portion 31A. In other words, the outer portion of the reinforcing material 4 may be embedded in the outer shell portion 31A and integrated with the outer shell portion 31A.

[0047] 6 and 7, the height of the outer shell portion 31A gradually increases as the process proceeds. When the outer shell portion 31A reaches a predetermined height, the ejection of the molding material a from the first nozzle 11 is completed. The outer shell portion 31A is formed along the outside of the reinforcing material 4.

[0048] As shown in FIG. 5, in the inner shell molding process, the second nozzle 21 of the second manufacturing device 2 ejects the molding material b toward the inside of the reinforcing material 4. When viewed from above, the second nozzle 21 moves circumferentially, makes one revolution, then moves upward, and repeats this process. The injection direction of the second nozzle 21 may be horizontal, diagonally downward, or diagonally upward. The molding material b deposited from the second nozzle 21 forms a cylindrical inner shell 32A whose axis is in the vertical direction. As shown in FIG. 8, the inner shell 32A contains the reinforcing material 4. The inner shell 32A is disposed inside the outer shell 31A. A structural member 3A is manufactured in which the outer shell 31A and the inner shell 32A are continuously integrated in the radial direction.

[0049] The first manufacturing apparatus 1 and the second manufacturing apparatus 2 are operated simultaneously. While the outer shell forming process for forming the outer shell portion 31A is proceeding, the inner shell forming process for forming the inner shell portion 32A is proceeding simultaneously. In other words, while the molding material a is being layered from the first nozzle 11, the molding material b is being sprayed from the second nozzle 21.

[0050] In the manufacturing method for a structural member configured in this manner, a cylindrical outer shell 31A is formed by a first manufacturing apparatus 1 in an outer shell forming process, and an inner shell 32A is formed inside the outer shell 31 by a second manufacturing apparatus 2 in an inner shell forming process. After the outer shell 31A is formed by the first manufacturing apparatus 1, the second manufacturing apparatus 2 sprays it toward the inside, so there is no need for the second manufacturing apparatus 2 to orbit the outer periphery of the outer shell 31A after forming the outer shell 31A. The second manufacturing apparatus 2 only needs to be positioned inside the outer shell 31A, and as there is no need to move the second manufacturing apparatus 2 significantly, a compact apparatus can be constructed.

[0051] In addition, the molding material b is sprayed from the second manufacturing device 2 toward the reinforcing material 4 installed in the reinforcing material placement process. Thus, the inner shell portion 32 including the reinforcing material 4 is formed, thereby increasing the strength of the structural member 3A.

[0052] Furthermore, even if the reinforcing material 4 has already been installed, the structural member 3A can be manufactured so as to cover the reinforcing material 4.

[0053] (Third embodiment) Next, a third embodiment of the present invention will be described mainly with reference to FIG.

[0054] FIG. 9 is a perspective view showing a method for manufacturing a structural member according to a third embodiment of the present invention. 9, in the manufacturing method of a structural member according to this embodiment, after the outer shell 31 is formed by the first manufacturing apparatus 1 as shown in the outer shell forming step of the first embodiment, the first manufacturing apparatus 1 is turned sideways so that the axis of the outer shell 31 faces horizontally. In the inner shell forming step, the second nozzle 21 of the second manufacturing apparatus 2 moves circumferentially inside the outer shell 31 as viewed from the horizontal direction, making one revolution, then moving horizontally away from the support stand P, making one revolution in the circumferential direction, and then moving horizontally away from the support stand P, repeating this process.

[0055] In the manufacturing method for a structural member configured in this manner, a cylindrical outer shell 31 is formed by a first manufacturing apparatus 1 in an outer shell forming process, and an inner shell 32 is formed inside the outer shell 31 by a second manufacturing apparatus 2 in an inner shell forming process. After the outer shell 31 is formed by the first manufacturing apparatus 1, the second manufacturing apparatus 2 sprays it toward the inside, so there is no need for the second manufacturing apparatus 2 to circle around the outer shell 31 after forming the outer shell 31. The second manufacturing apparatus 2 only needs to be positioned inside the outer shell 31, so the apparatus can be made compact.

[0056] Furthermore, in the inner shell molding process, the outer shell 31 is laid on its side to mold the inner shell 32, resulting in the structural member 3 being molded with its axis oriented horizontally. This has the advantage of making it easier to lift the structural member 3 after manufacturing.

[0057] (Variations 1 to 3) Next, first to third modifications of the embodiment of the present invention will be described mainly with reference to FIGS. Fig. 10 is a perspective view showing a structural member manufactured by a manufacturing method for a structural member according to a first modified embodiment of the present invention. Fig. 11 is a perspective view showing a structural member manufactured by a manufacturing method for a structural member according to a second modified embodiment of the present invention. Fig. 12 is a perspective view showing a structural member manufactured by a manufacturing method for a structural member according to a third modified embodiment of the present invention. 10 to 12, in the outer shell molding process, irregularities may be formed on the outer peripheral surface of the outer shell 31. The control unit positions the first nozzle 11 of the first manufacturing device 1 at a position corresponding to the irregularities of the outer shell 31 to be molded, and dispenses the modeling material a.

[0058] As in Modification 1 shown in Fig. 10, nodes may be provided on the outer peripheral surface of the outer shell portion 31. The nodes are formed in an annular shape so as to protrude radially outward from the outer peripheral surface of the outer shell portion 31. A plurality of nodes are arranged at intervals in the axial direction of the outer shell portion 31.

[0059] The recesses (protrusions) may be arranged in a spiral shape, as in Modification 2 shown in Figure 11. The recesses and protrusions are arranged alternately in the axial direction of the outer shell portion 31.

[0060] As shown in Modification 3 in FIG. 12, the shape may be wavy with recesses and protrusions alternately formed in the circumferential direction.

[0061] Alternatively, the discharge port 11a of the first nozzle 11 of the first manufacturing apparatus 1 may have a trapezoidal cross section along the radial direction, thereby forming the unevenness.

[0062] In the manufacturing method for a structural member configured in this manner, a cylindrical outer shell 31 is formed by a first manufacturing apparatus 1 in an outer shell forming process, and an inner shell 32 is formed inside the outer shell 31 by a second manufacturing apparatus 2 in an inner shell forming process. After the outer shell 31 is formed by the first manufacturing apparatus 1, the second manufacturing apparatus 2 sprays it toward the inside, so there is no need for the second manufacturing apparatus 2 to circle around the outer shell 31 after forming the outer shell 31. The second manufacturing apparatus 2 only needs to be positioned inside the outer shell 31, so the apparatus can be made compact.

[0063] In the outer shell molding process, the molding material a is discharged in layers from the first nozzle 11 of the first manufacturing device 1, so even complex shapes such as those shown in Modifications 1 to 3 can be manufactured freely and with high precision.

[0064] Furthermore, by forming irregularities on the outer peripheral surface of the outer shell 31, the specific surface area of ​​the outer peripheral surface of the outer shell 31 is increased. Therefore, when the structural member 3 is buried as a pile, the friction area with the soil layer increases, and the friction force can be improved.

[0065] The shapes and combinations of the components shown in the above-described embodiment are merely examples, and various modifications can be made based on design requirements, etc., within the scope of the present invention.

[0066] For example, in the first embodiment, the inner shell molding process for molding the inner shell portion 32 proceeds simultaneously with the outer shell portion molding process for molding the outer shell portion 31, but this is not limited to this. The second manufacturing apparatus 2 may be operated after the operation of the first manufacturing apparatus 1 has finished. In other words, the inner shell molding process for molding the inner shell portion 32 may proceed after the molding of the outer shell portion 31 has been completed in the outer shell portion molding process. In this case, when manufacturing one structural member 3, crossing or interference between the first manufacturing apparatus 1 and the second manufacturing apparatus 2 is suppressed, allowing the work to proceed smoothly.

[0067] Furthermore, in the second embodiment, the outer shell molding process is performed after the reinforcing material placement process, but this is not limited to this. The reinforcing material placement process may also be performed after the outer shell molding process. In the reinforcing material placement process, the reinforcing material 4 is placed inside the outer shell 31A formed in the outer shell molding process. In the inner shell molding process, the molding material b is sprayed from the second manufacturing device 2 toward the reinforcing material 4. This results in the formation of an inner shell 32A that is integrated with the outer shell 31A and contains the reinforcing material 4.

[0068] Furthermore, in the second embodiment, the reinforcing member 4 includes a plurality of axial reinforcing bars 41 and a plurality of hoop reinforcing bars 42, but is not limited to this. The reinforcing member 4 may be arranged inside the outer shell portion 31 and have the function of increasing the strength of the structural member 3. For example, the reinforcing member may be composed of a plurality of reinforcing bars arranged in a spiral shape. The reinforcing member may be formed in a mesh shape from a steel material. The reinforcing member may be composed of a plurality of curved plate members arranged with the plate surfaces facing radially and spaced apart in the circumferential direction.

[0069] Furthermore, the support table P on which the structural member 3 is placed may have a rotating mechanism. The rotation speed may be controlled by a control unit. By controlling the control units of the first manufacturing device 1 and the second manufacturing device 2, and the control unit that rotates the support table P, the structural member 3 can be manufactured more efficiently. In other words, the rotation of the support table P means that the first manufacturing device 1 and the second manufacturing device 2 only need to operate in the vertical direction, making it possible to manufacture members with minimal operation.

[0070] Furthermore, when increasing the radial thickness of the first manufacturing apparatus 1, the outer shell molding step may be repeated to mold another layer of outer shell 31 on the outside of the outer shell 31 molded in the outer shell molding step. Alternatively, the inner shell molding step may be repeated to mold another layer of inner shell 32 on the inside of the inner shell 32 molded in the inner shell molding step.

[0071] Furthermore, when manufacturing one structural member 3, a plurality of first manufacturing devices 1 may be operated simultaneously, and a plurality of second manufacturing devices 2 may be operated simultaneously. By operating a plurality of first manufacturing devices 1 and second manufacturing devices 2 simultaneously, the structural member 3 can be manufactured more efficiently.

[0072] In the embodiment described above, the manufacturing equipment used in the outer shell molding process is the first manufacturing equipment 1, and the manufacturing equipment used in the inner shell molding process is the second manufacturing equipment 2, and the manufacturing equipment used in the outer shell molding process and the inner shell molding process are different, but this is not limited to this. The outer shell molding process and the inner shell molding process may be performed by a single manufacturing equipment.

[0073] In the above embodiment, the inside of the structural member 3 is formed hollow, but this is not limited to this. A solid structural member can also be manufactured by injecting the molding material b so as to fill the entire inside of the outer shell 31 in the inner shell molding process.

[0074] The Sustainable Development Goals (SDGs) are 17 international goals adopted at the United Nations Summit in September 2015. The manufacturing method for a structural member and the structural member according to this embodiment can contribute to achieving one of the 17 SDGs, for example, goal 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization, and foster innovation." [Explanation of symbols]

[0075] 1 1st manufacturing equipment (manufacturing equipment) 2 2nd manufacturing equipment (manufacturing equipment) 3 Structural members 4 Reinforcement 31,1A Outer shell 32,32A Inner shell a,b Building materials a,b Building materials

Claims

1. an outer shell forming process in which a molding material is stacked or sprayed from a manufacturing device from below to above to form a cylindrical outer shell having an axial direction in the up-down direction; A manufacturing method for a structural member, comprising: an inner shell molding process in which a molding material is sprayed from the manufacturing device toward the inside of the outer shell to mold an inner shell inside the outer shell.

2. the manufacturing apparatus in the outer shell portion molding step is a first manufacturing apparatus, The manufacturing apparatus for the inner shell portion forming step is a second manufacturing apparatus, The method for manufacturing a structural member according to claim 1 , wherein the manufacturing device for the outer shell portion molding step is different from the manufacturing device for the inner shell portion molding step.

3. The method for manufacturing a structural member according to claim 1 or 2, wherein the inside of the inner shell portion is formed to be hollow.

4. The method for manufacturing a structural member according to claim 2, wherein the inner shell forming step of forming the inner shell portion is carried out simultaneously with the outer shell portion forming step of forming the outer shell portion.

5. 3. The method for manufacturing a structural member according to claim 1, wherein the inner shell molding step of molding the inner shell is carried out after the outer shell molding step has completed molding the outer shell.

6. a reinforcing material arranging step of arranging a reinforcing material inside the outer shell portion, The method for manufacturing a structural member according to claim 1 or 2, wherein in the inner shell molding step, the molding material is sprayed from the manufacturing device toward the reinforcing material to mold the inner shell including the reinforcing material.

7. a reinforcing material arranging step of arranging a reinforcing material, In the outer shell forming step, the outer shell is formed on the outside of the reinforcing material, The method for manufacturing a structural member according to claim 1 or 2, wherein in the inner shell molding step, the molding material is sprayed from the manufacturing device toward the reinforcing material to mold the inner shell including the reinforcing material.

8. a cylindrical shell portion formed by stacking or spraying a modeling material discharged from a manufacturing device and hardening the material, with the shell portion having an axial direction extending in the vertical direction; A structural member comprising an inner shell portion formed inside the outer shell portion by spraying a molding material ejected from the manufacturing device toward the inside of the outer shell portion and hardening it.

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